JPH08250263A - Three-phase silicon carbide heater - Google Patents

Abstract

PURPOSE: To provide a three-phase silicon carbide heater in which heat generation from the center and a tip part is intense and heat distribution is uniform and as a result with high heat generation efficiency. CONSTITUTION: A slurry containing silicon carbide is cast and formed in order to produce a three-phase silicon carbide heater which consists of a center heat generating part 12, two heat generating end parts 16, and a tip end part to joint the two heat generating end parts 14 with the center heat generating part 12. The tip end part is shaped into a W-shape and the center heat generating part 12 and these two heat generating end parts 14 are insulated on the same plane.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a three-phase type silicon carbide heating element, and more particularly to a three-phase type silicon carbide heating element having high heat generation efficiency and uniform heat generation distribution.

[0002]

2. Description of the Related Art A conventional three-phase silicon carbide heating element is disclosed in Japanese Patent Application Laid-Open No. 4-230985, which has a heating portion formed by casting a sludge containing silicon carbide. Three-phase silicon carbide heating elements are known.
As shown in FIG. 6, the heating element 200 includes a linearly extending tip portion 201, a central heating portion 202-1 that extends in a direction orthogonal to the tip portion 201, and is equally formed at equal intervals.
It is composed of end heat generating parts 202-2 and 202-3. Each heating unit 2
02, the one end of the central connecting portion 206-1 and the end connecting portions 206-2, 206-3 are bonded to the end portion on the opposite side of the tip portion 201, and the connecting portions 206-1, 206-2, 2-2.
At the other end of 06-3, the central electrode 210-1,
And end electrodes 210-2 and 210-3 are attached.

[0003]

In the three-phase silicon carbide heating element disclosed in Japanese Patent Laid-Open No. 4-230985 mentioned above, the current flowing through the central heating portion 202-1 is the end heating portion 202-2. , 202-3, respectively, and therefore the amount of heat generated in the central portion is larger than the amount of heat generated in the end portions, and the heat generation of the heat generating element 200 is not uniform and the heat generation efficiency is low.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the conventional three-phase silicon carbide heating element, and the heating portion and the tip portion generate strong heat and have a uniform heat distribution. As a result, it is an object of the present invention to provide a three-phase type silicon carbide heating element having a high heating efficiency.

[0005]

According to the present invention, a sludge containing silicon carbide is cast and formed, and a heating part having a central heating part and two end heating parts, the central heating part and two end heating parts are provided. In a three-phase silicon carbide heating element including a tip portion for connection, the tip portion is formed in a W shape, and the central heating portion and two end heating portions are arranged in one plane. Is a three-phase type silicon carbide heating element. In the present invention, the central heating portion is longer than the end heating portion. In the present invention, the central heating portion is formed thicker than the end heating portion. In the present invention, further, the central heating portion and the two end heating portions are formed with the same interval. In the present invention, the central heating portion and the two end heating portions are formed with different intervals.

[0006]

[First Embodiment] A three-phase silicon carbide heating element according to an embodiment of the present invention will be described below with reference to the drawings. As shown in FIG. 1, the three-phase silicon carbide heating element 1 according to the first embodiment has a tip 10 having a circular cross section and a W shape with the same thickness, and a tip 10.
A central heat generating portion 12, end heat generating portions 14, 16 extending in parallel with each other from the three ends of the tip portion 10 in the same cross section as
And extending parallel to each other from the ends of the heat generating parts 12, 14, 16 opposite to the tip part 10, and attached to the ends of the central connecting part 20, end connecting parts 22, 24 having the same cross section as the tip part 10. It is composed of electrodes 30, 32 and 34. Heat generating parts 12, 1
4, 16, the central connecting portion 20, the end connecting portions 22, 24, the electrodes 30, 32, 34 have a diameter of 20 mm and the heat generating portions 12, 1
The distance between the centers of 4 and 16 is 52 mm, and the tip portion 10 (W type portion)
Has a height of 36 mm, the center of the top of the tip 10 (W-shaped portion) has a height of 52 mm, and the total height of the tip 10 and the central heating portion 12 is 280 mm. , 16 has a total height of 280 mm, the central connecting portion 20 has a length of 270 mm, and the end connecting portions 22 and 24 have a length of 270 m.
m, the length of the electrodes 30, 32, 34 is 40 mm.

The tip portion 10 and the heat generating portions 12, 14 and 16 are composed of 100 parts by weight of silicon carbide powder, 1.5 parts by weight of a wax emulsion acting as a binder and 0.04 parts by weight of vinyl alcohol acting as a dispersant. Parts, 0.16 parts by weight of ammonia, and 14 parts by weight of ion-exchanged water acting as a dispersion medium are pulverized and mixed by a ball mill for 16 hours to form a slurry containing silicon carbide, which is molded. Next, this molded body is subjected to a non-oxidizing atmosphere at 2500 ° C.
Bake for 30 minutes to obtain recrystallized silicon carbide. Connection part 2
0, 22, and 24 were mixed with 5 parts by weight of a cellulosic binder and 8 parts by weight of ion-exchanged water to 50 parts by weight of silicon carbide and 50 parts by weight of carbon, molded into a diameter of 20 mm, and then impregnated with silicon. It is formed by reaction sintering. Connecting parts 20, 2
2, 24 are attached to the heat generating parts 12, 14, 16 by welding. The electrodes 30, 32, 34 are formed on the connecting portions 20, 22, 24 by thermal spraying, and a three-phase voltage is applied from the power source 40.

[0008]

[Comparative Experiment 1] A comparative experiment was conducted using the three-phase silicon carbide heating element of the first embodiment. As shown in FIG. 6, the conventional three-phase silicon carbide heating element used for comparison has a heating portion and a connecting portion with a diameter of 20 mm and a heating portion center interval of 52 mm.
mm, height of tip part (W-shaped part) is 36 mm, length of central connecting part is 270 mm, length of end connecting part is 270 mm Length of electrode parts 210-1, 210-2, 210-3 Is 40 mm
Is. The first comparative measurement is, as shown in FIG.
0 and the measurement points (1) on the heating sections 12, 14, 16;
The temperatures of (2), (3), (4) and (5) were measured. The conventional heating element used for comparison is shown in FIG. 6, and the temperature at the same position as in the first embodiment shown in FIG. 2 was measured. Two-phase AC power of 2.2 Kw was applied to each heating element. The measurement results are as follows.

Heating Element of First Example Conventional Heating Element Measuring Point (1) 1000 ° C. 1000 ° C. Measuring Point (2) 1022 1024 Measuring Point (3) 1007 1011 Measuring Point (4) 1014 918 Measuring Point (5) 993 906 Measurement points (1), (2) by the heating element of the first embodiment,
The temperatures of (3), (4) and (5) were much more uniform than those of the conventional heating element of FIG.

[0010]

[Second Embodiment] Three-phase silicon carbide heating element 1 of the second embodiment.
No. 00 makes the length of the central heat generating portion longer than the length of the two end heat generating portions. As shown in FIG. 2, it is made of the same material and the same method as the first embodiment. In the third embodiment, the same components as those in the first embodiment are designated by the same reference numerals as those in the first embodiment in FIG. 3 and their description is omitted. Exothermic parts 12, 14, 16, central connecting part 20, end connecting part 2
2, 24, electrodes 30, 32, 34 have a diameter of 20 m
m, the center interval between the starting portions 12, 14, 16 is 52 mm, the height of the tip 10 (W-shaped portion) is 36 mm, the tip 10
The center distance of the top of (W-shaped part) is 52 mm, the tip 1
The total height of 0 and the central heating portion 12 is 270 mm, and the total height of the tip portion 10 and the end heating portions 14 and 16 is 250 mm.
mm, the length of the end connecting portions 22, 24 is 350 mm, the length of the central connecting portion 20 is 330 mm, and the length of the electrodes 30, 32, 34 is 40 mm.

[0011]

[Comparative Experiment 2] A comparative experiment was conducted using the three-phase heating element of the second embodiment. As shown in FIG. 3, measurement points (1), (2), (3) of the three-phase silicon carbide heating element 100,
(4), (5) and the measurement point (6) of the alumina plate 50,
The temperatures of (7), (8), (9) and (10) were measured.
The conventional three-phase silicon carbide heating element used for comparison has the same shape as that shown in FIG. 6, the diameter of the heating portion and the connecting portion is 20 mm, and the center distance between the heating portions is 52 m.
m, the total height of the heat generating portion and the connecting portion is 635 mm, the length of the tip portion is 140 mm, and the length of the connecting portion is 310 mm. As shown in FIG. 3, the comparative experiment 2 was performed with the alumina plate 5
Three-phase silicon carbide heating element 100 was arranged above 0 so that the height to the tip was 500 mm. Two-phase AC power of 2.2 Kw was applied to each heating element. Heating element of the second example Conventional heating element Measuring point (1) 1000 ° C. 1000 ° C. measuring point (2) 1014 1026 measuring point (3) 1007 1013 measuring point (4) 996 919 measuring point (5) 1004 906 measuring point (6) 750 730 Measurement point (7) 732 713 Measurement point (8) 719 709 Measurement point (9) 708 686 Measurement point (10) 708 682 Surface temperature of three-phase silicon carbide heating element Is much more uniform than the conventional heating element, and the object to be heated can be heated more uniformly and at a higher temperature, which indicates that the heating element has higher efficiency than the conventional heating element.

[0012]

[Third Embodiment] Three-phase silicon carbide heating element 1 of the third embodiment.
00 is thicker than the thickness of the two end heat generating portions in the central heat generating portion, and is shown in FIG. 4, and is made of the same material as that of the first embodiment by the same method. The same components as those of the first embodiment are designated by the same reference numerals as those of the first embodiment in FIG. 4 and their description is omitted. The thickness of the central heating portion 12, the central connecting portion 20, the end connecting portions 22 and 24, the electrodes 30, 32 and 34 is 20 mm in diameter, and the thickness of the two end heating portions 14 and 16 is 19 mm. , 16 has a center interval of 52
mm, the height of the tip 10 (W-shaped portion) is 36 mm, the center distance between the tops of the tip 10 (W-shaped portion) is 52 mm, and the total height of the tip 10 and the central heating portion 12 is 270 mm. ,
The total height of the tip portion 10 and the end heat generating portions 14 and 16 is 2
50 mm, the height of the end connecting portions 22, 24 is 350 mm, the height of the central connecting portion 20 is 330 mm, the electrodes 30, 32, 34
The height is 40 mm.

[0013]

[Comparative Experiment 3] The conventional three-phase silicon carbide heating element used for comparison is the same as that used in the second comparative example, and 2.2 Kw for each heating element as in the second comparative example. Three-phase AC power was applied. As shown in FIG. 3, measurement points (1), (2), (3) of the three-phase type silicon carbide heating element 100,
(4), (5) and the measurement point (6) of the alumina plate 50,
The temperatures of (7), (8), (9) and (10) were measured. Heating Element of Third Example Conventional Heating Element Measurement Point (1) 1000 ° C. 1000 ° C. Measurement Point (2) 1008 1024 Measurement Point (3) 998 1011 Measurement Point (4) 990 918 Measurement Point (5) 988 906 Measurement Point (6) 1006 729 Measuring point (7) 743 718 Measuring point (8) 731 708 Measuring point (9) 712 687 Measuring point (10) 706 682 By this comparative experiment 3, the surface temperature of the three-phase silicon carbide heating element was measured. Is much more uniform than the conventional heating element, and the object to be heated can be heated more uniformly and at a higher temperature, which indicates that the heating element has higher efficiency than the conventional heating element.

[0014]

[Fourth Embodiment] Three-phase silicon carbide heating element 1 of the fourth embodiment.
Reference numeral 00 denotes a gap between the central heating portion and the two end heating portions, which is shown in FIG. 5, and is manufactured by the same method and using the same material as in the first embodiment. The same components are assigned the same reference numerals as those in the first embodiment in FIG. 5 and their description is omitted. Central heat generating part 12, central connecting part 2
0, the end connecting portions 22, 24, the electrodes 30, 32, 34 have a diameter of 20 mm, and the two end heating portions 14, 16 have a thickness of
The center distance between the 19 mm heat generating portions 12 and 14 is 52 mm, the center distance between the heat generating portions 12 and 16 is 48 mm, and the tip portion 10 (W
The height of the shaped portion) is 36 mm, the center distance between the tops of the tip portions 10 (W shaped portion) is 48 mm, and the total height of the tip portion 10 and the central heating portion 12 is 270 mm. The total height of 14 and 16 is 250mm, the end connecting part 2
The length of 2 and 24 is 350 mm, the length of the central connecting portion 20 is 330 mm, and the length of the electrodes 30, 32 and 34 is 40 mm.
Is.

[0015]

[Comparative Experiment 4] Comparative Experiment 4 was conducted using the three-phase silicon carbide heating element of the fourth embodiment. That is, two of the three-phase silicon carbide heating elements 100 of the fourth embodiment are mounted in the electric furnace 110 shown in FIG. 5, and electric power is applied so that the temperature indicated by the control thermoelectric element 112 becomes 900 ° C. did. At that time, the temperature distribution at 5 points in each part of the furnace was measured. The conventional three-phase silicon carbide heating element used for comparison is the same as that used in the second comparative example, and like the three-phase silicon carbide heating element 100 of the fourth comparative example, the electric furnace. Two pieces were mounted in 110 and electric power was applied so that the temperature indicated by the control thermocouple 112 would be 900 ° C. At that time, 5 points of temperature distribution of each part in the furnace were measured. Heating Element of Fourth Example Conventional Heating Element Measuring Point (1) 900 ° C. 900 ° C. Measuring Point (2) 902 903 Measuring Point (3) 904 901 Measuring Point (4) 898 896 Measuring Point (5) 897 894 This Comparison Experiment 4 shows that the three-phase silicon carbide heating element of the present invention has a uniform temperature distribution up to the vicinity of the furnace wall and is a highly efficient heating element by the conventional three-phase silicon carbide heating element. Be done.

[0016]

According to the present invention as set forth in claim 1, as compared with the conventional three-phase type silicon carbide heating element, the heating portion and the tip portion generate more heat and the heat distribution is uniform, resulting in heat generation. A highly efficient three-phase silicon carbide heating element can be provided. According to the second aspect of the present invention, the temperature distribution can be made more uniform than that of the three-phase silicon carbide heating element of the present invention according to the first aspect, and as a result, the three-phase type silicon carbide heat generation having high heat generation efficiency is achieved. The body can be provided. According to the present invention as set forth in claim 3, the temperature distribution can be made more uniform than that of the three-phase type silicon carbide heating element of the present invention as set forth in claim 1, and as a result, the three-phase type silicon carbide heat generation having a high heat generation efficiency is achieved. The body can be provided.
According to the invention of claim 4, the temperature distribution of the object to be heated can be made more uniform than that of the conventional three-phase type silicon carbide heating element, and as a result, a three-phase type silicon carbide heating element having high heat generation efficiency is provided. can do. According to the present invention of claim 5, the temperature distribution in the furnace can be made more uniform than that of the conventional three-phase silicon carbide heating element,
As a result, it is possible to provide a three-phase silicon carbide heating element having a high heating efficiency.

[Brief description of drawings]

FIG. 1 is a plan view of a three-phase silicon carbide heating element according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram showing the positions of measurement points in comparative experiment 1.

FIG. 3 is an explanatory diagram showing the positions of three-phase silicon carbide heating elements and measurement points in Comparative Experiments 2 and 3.

FIG. 4 is a plan view of a three-phase silicon carbide heating element according to a third embodiment of the present invention.

5 is an explanatory diagram showing the positions of three-phase silicon carbide heating elements and measurement points in comparative experiment 4. FIG.

FIG. 6 is a plan view of a conventional three-phase silicon carbide heating element.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Three-phase type silicon carbide heating element 10 Tip part 12 Central heating part 14, 16 End heating part 20 Central connecting part 22, 24 End connecting part 30, 32, 34 Electrode 40 Power supply 100 Three-phase type silicon carbide heating element 104 Measurement point 110 Electric furnace 112 Control thermocouple 200 Three-phase silicon carbide heating element 201 Tip part 202 Heating part 206-1 Central connecting part 206-1, 206-2 End connecting part 210-1 Electrode 210-2 Electrode 210ー 3 electrodes

Claims (5)

[Claims] 1. A cast containing a silicon carbide-containing slurry,
A three-phase silicon carbide heating element comprising a heating section having a central heating section and two end heating sections, and a tip section for connecting the central heating section and the two end heating sections, wherein the tip is A three-phase silicon carbide heating element characterized in that the portion is formed in a W shape, and the central heating portion and the two end heating portions are arranged in one plane. 2. The three-phase type silicon carbide heating element according to claim 1, wherein the central heating portion is formed longer than the two end heating portions. 3. The three-phase type silicon carbide heating element according to claim 1, wherein the central heating portion is formed thicker than the two end heating portions. 4. The three-phase type silicon carbide heating element according to claim 1, wherein the central heating portion and the two end heating portions are formed at equal intervals. 5. The central heating portion and the two end heating portions are formed with different intervals.
The three-phase silicon carbide heating element described.